\end{align*}$\agm(-)$ is a locally non-expansive bifunctor from $\COFEs$ to $\CMRAs$.The reason we store a \emph{chain}$c$ of elements of $T$, rather than a single element, is that $\agm(\cofe)$ needs to be a COFE itself, so we need to be able to give a limit for every chain.\ralf{Figure out why exactly this is not possible without adding an explicit chain here.}